Allergies

Allergies are abnormal immune system reactions to things that are typically harmless to most people. When you’re allergic to something, your immune system 1 believes that this substance is harmful to your body. Substances that cause allergic reactions — such as certain foods, dust, plant pollen, or medicines — are known as allergens. In an attempt to 2 the body, the immune system produces IgE antibodies to that allergen. Those antibodies then cause certain cells in the body to 3 chemicals into the bloodstream, one of which is histamine. The histamine then 4 on a person's eyes, nose, throat, lungs, skin, or gastrointestinal tract and causes the symptoms of the allergic reaction. Future exposure to that same allergen will trigger this 5 response again. This means that every time you come into contact with that allergen, you'll have an allergic reaction.